Nuclear Energy

Nuclear energy originates from the splitting of uranium atoms in a process called fission. Fission releases energy that can be used to make steam, which is used in a turbine to generate electricity. Nuclear power accounts for approximately 19 percent of the United States' electricity production. More than 100 nuclear generating units are currently in operation in the United States, though none have been built since 1996.

Uranium is a nonrenewable resource that cannot be replenished on a human time scale. Uranium is extracted from open-pit and underground mines. Once mined, the uranium ore is sent to a processing plant to be concentrated into a useful fuel. This uranium enrichment process generates radioactive waste. Although power plants are regulated by federal and state laws to protect human health and the environment, there is a wide variation of environmental impacts associated with power generation technologies: air emissions, nuclear waste generation, water discharge, water resource use and land resource use. (Source: EPA / Photo: Flickr)

Video: The Japanese government is pledging $500 million to build a wall of frozen earth around the Fukushima nuclear power plant, which has been leaking radioactive water since it was damaged in the 2011 tsunami.